A review of stemflow generation dynamics and stemflow-environment interactions in forests and shrublands

Many geoscientists now recognize stemflow as an important phenomenon which can exert considerable effects on the hydrology, biogeochemistry, and ecology of wooded ecosystems and shrublands. Despite the explosive growth of stemflow research, until this review there has been no comprehensive attempt to summarize and synthesize this literature since 2003. Topical areas of substantive new knowledge in stemflow research include the following: (1) the interrelationships among stemflow and meteorological conditions, especially within individual rain events; (2) the dynamic interplay between stemflow and canopy structure; (3) stemflow and the cycling of solutes and transport of particulate matter; (4) stemflow and its interactions with canopy fungi and corticolous lichens; and (5) stemflow-soil interactions. Each of these five topical areas of substantive new stemflow research is summarized and synthesized, with areas of future research opportunities discussed. In addition, we have reviewed the parameters which can be used to describe stemflow and critically evaluate their utility for different purposes. This review makes a call for scientists studying stemflow to utilize common metrics in an effort to increase the cross-site comparability of stemflow studies. Capitalizing on the insights of prior research, exciting research opportunities await hydrologists, biogeoscientists, and forest ecologists who will conduct studies to deepen our knowledge of stemflow which will enable a better and more accurate framing of stemflow in the larger context of watershed hydrology and biogeochemistry.